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 * Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
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package java.net;

import java.io.ObjectStreamException;

/**
 * This class represents an Internet Protocol version 4 (IPv4) address.
 * Defined by <a href="http://www.ietf.org/rfc/rfc790.txt">
 * <i>RFC&nbsp;790: Assigned Numbers</i></a>,
 * <a href="http://www.ietf.org/rfc/rfc1918.txt">
 * <i>RFC&nbsp;1918: Address Allocation for Private Internets</i></a>,
 * and <a href="http://www.ietf.org/rfc/rfc2365.txt"><i>RFC&nbsp;2365:
 * Administratively Scoped IP Multicast</i></a>
 *
 * <h3> <A NAME="format">Textual representation of IP addresses</a> </h3>
 *
 * Textual representation of IPv4 address used as input to methods
 * takes one of the following forms:
 *
 * <blockquote><table cellpadding=0 cellspacing=0 summary="layout">
 * <tr><td>{@code d.d.d.d}</td></tr>
 * <tr><td>{@code d.d.d}</td></tr>
 * <tr><td>{@code d.d}</td></tr>
 * <tr><td>{@code d}</td></tr>
 * </table></blockquote>
 *
 * <p> When four parts are specified, each is interpreted as a byte of
 * data and assigned, from left to right, to the four bytes of an IPv4
 * address.
 *
 * <p> When a three part address is specified, the last part is
 * interpreted as a 16-bit quantity and placed in the right most two
 * bytes of the network address. This makes the three part address
 * format convenient for specifying Class B net- work addresses as
 * 128.net.host.
 *
 * <p> When a two part address is supplied, the last part is
 * interpreted as a 24-bit quantity and placed in the right most three
 * bytes of the network address. This makes the two part address
 * format convenient for specifying Class A network addresses as
 * net.host.
 *
 * <p> When only one part is given, the value is stored directly in
 * the network address without any byte rearrangement.
 *
 * <p> For methods that return a textual representation as output
 * value, the first form, i.e. a dotted-quad string, is used.
 *
 * <h4> The Scope of a Multicast Address </h4>
 *
 * Historically the IPv4 TTL field in the IP header has doubled as a
 * multicast scope field: a TTL of 0 means node-local, 1 means
 * link-local, up through 32 means site-local, up through 64 means
 * region-local, up through 128 means continent-local, and up through
 * 255 are global. However, the administrative scoping is preferred.
 * Please refer to <a href="http://www.ietf.org/rfc/rfc2365.txt">
 * <i>RFC&nbsp;2365: Administratively Scoped IP Multicast</i></a>
 *
 * @since 1.4
 */

public final class Inet4Address extends InetAddress {

  final static int INADDRSZ = 4;

  /**
   * use serialVersionUID from InetAddress, but Inet4Address instance
   * is always replaced by an InetAddress instance before being
   * serialized
   */
  private static final long serialVersionUID = 3286316764910316507L;

  /*
   * Perform initializations.
   */
  static {
    init();
  }

  Inet4Address() {
    super();
    holder().hostName = null;
    holder().address = 0;
    holder().family = IPv4;
  }

  Inet4Address(String hostName, byte addr[]) {
    holder().hostName = hostName;
    holder().family = IPv4;
    if (addr != null) {
      if (addr.length == INADDRSZ) {
        int address = addr[3] & 0xFF;
        address |= ((addr[2] << 8) & 0xFF00);
        address |= ((addr[1] << 16) & 0xFF0000);
        address |= ((addr[0] << 24) & 0xFF000000);
        holder().address = address;
      }
    }
  }

  Inet4Address(String hostName, int address) {
    holder().hostName = hostName;
    holder().family = IPv4;
    holder().address = address;
  }

  /**
   * Replaces the object to be serialized with an InetAddress object.
   *
   * @return the alternate object to be serialized.
   * @throws ObjectStreamException if a new object replacing this object could not be created
   */
  private Object writeReplace() throws ObjectStreamException {
    // will replace the to be serialized 'this' object
    InetAddress inet = new InetAddress();
    inet.holder().hostName = holder().getHostName();
    inet.holder().address = holder().getAddress();

    /**
     * Prior to 1.4 an InetAddress was created with a family
     * based on the platform AF_INET value (usually 2).
     * For compatibility reasons we must therefore write the
     * the InetAddress with this family.
     */
    inet.holder().family = 2;

    return inet;
  }

  /**
   * Utility routine to check if the InetAddress is an
   * IP multicast address. IP multicast address is a Class D
   * address i.e first four bits of the address are 1110.
   *
   * @return a {@code boolean} indicating if the InetAddress is an IP multicast address
   * @since JDK1.1
   */
  public boolean isMulticastAddress() {
    return ((holder().getAddress() & 0xf0000000) == 0xe0000000);
  }

  /**
   * Utility routine to check if the InetAddress in a wildcard address.
   *
   * @return a {@code boolean} indicating if the Inetaddress is a wildcard address.
   * @since 1.4
   */
  public boolean isAnyLocalAddress() {
    return holder().getAddress() == 0;
  }

  /**
   * Utility routine to check if the InetAddress is a loopback address.
   *
   * @return a {@code boolean} indicating if the InetAddress is a loopback address; or false
   * otherwise.
   * @since 1.4
   */
  public boolean isLoopbackAddress() {
        /* 127.x.x.x */
    byte[] byteAddr = getAddress();
    return byteAddr[0] == 127;
  }

  /**
   * Utility routine to check if the InetAddress is an link local address.
   *
   * @return a {@code boolean} indicating if the InetAddress is a link local address; or false if
   * address is not a link local unicast address.
   * @since 1.4
   */
  public boolean isLinkLocalAddress() {
    // link-local unicast in IPv4 (169.254.0.0/16)
    // defined in "Documenting Special Use IPv4 Address Blocks
    // that have been Registered with IANA" by Bill Manning
    // draft-manning-dsua-06.txt
    int address = holder().getAddress();
    return (((address >>> 24) & 0xFF) == 169)
        && (((address >>> 16) & 0xFF) == 254);
  }

  /**
   * Utility routine to check if the InetAddress is a site local address.
   *
   * @return a {@code boolean} indicating if the InetAddress is a site local address; or false if
   * address is not a site local unicast address.
   * @since 1.4
   */
  public boolean isSiteLocalAddress() {
    // refer to RFC 1918
    // 10/8 prefix
    // 172.16/12 prefix
    // 192.168/16 prefix
    int address = holder().getAddress();
    return (((address >>> 24) & 0xFF) == 10)
        || ((((address >>> 24) & 0xFF) == 172)
        && (((address >>> 16) & 0xF0) == 16))
        || ((((address >>> 24) & 0xFF) == 192)
        && (((address >>> 16) & 0xFF) == 168));
  }

  /**
   * Utility routine to check if the multicast address has global scope.
   *
   * @return a {@code boolean} indicating if the address has is a multicast address of global scope,
   * false if it is not of global scope or it is not a multicast address
   * @since 1.4
   */
  public boolean isMCGlobal() {
    // 224.0.1.0 to 238.255.255.255
    byte[] byteAddr = getAddress();
    return ((byteAddr[0] & 0xff) >= 224 && (byteAddr[0] & 0xff) <= 238) &&
        !((byteAddr[0] & 0xff) == 224 && byteAddr[1] == 0 &&
            byteAddr[2] == 0);
  }

  /**
   * Utility routine to check if the multicast address has node scope.
   *
   * @return a {@code boolean} indicating if the address has is a multicast address of node-local
   * scope, false if it is not of node-local scope or it is not a multicast address
   * @since 1.4
   */
  public boolean isMCNodeLocal() {
    // unless ttl == 0
    return false;
  }

  /**
   * Utility routine to check if the multicast address has link scope.
   *
   * @return a {@code boolean} indicating if the address has is a multicast address of link-local
   * scope, false if it is not of link-local scope or it is not a multicast address
   * @since 1.4
   */
  public boolean isMCLinkLocal() {
    // 224.0.0/24 prefix and ttl == 1
    int address = holder().getAddress();
    return (((address >>> 24) & 0xFF) == 224)
        && (((address >>> 16) & 0xFF) == 0)
        && (((address >>> 8) & 0xFF) == 0);
  }

  /**
   * Utility routine to check if the multicast address has site scope.
   *
   * @return a {@code boolean} indicating if the address has is a multicast address of site-local
   * scope, false if it is not of site-local scope or it is not a multicast address
   * @since 1.4
   */
  public boolean isMCSiteLocal() {
    // 239.255/16 prefix or ttl < 32
    int address = holder().getAddress();
    return (((address >>> 24) & 0xFF) == 239)
        && (((address >>> 16) & 0xFF) == 255);
  }

  /**
   * Utility routine to check if the multicast address has organization scope.
   *
   * @return a {@code boolean} indicating if the address has is a multicast address of
   * organization-local scope, false if it is not of organization-local scope or it is not a
   * multicast address
   * @since 1.4
   */
  public boolean isMCOrgLocal() {
    // 239.192 - 239.195
    int address = holder().getAddress();
    return (((address >>> 24) & 0xFF) == 239)
        && (((address >>> 16) & 0xFF) >= 192)
        && (((address >>> 16) & 0xFF) <= 195);
  }

  /**
   * Returns the raw IP address of this {@code InetAddress}
   * object. The result is in network byte order: the highest order
   * byte of the address is in {@code getAddress()[0]}.
   *
   * @return the raw IP address of this object.
   */
  public byte[] getAddress() {
    int address = holder().getAddress();
    byte[] addr = new byte[INADDRSZ];

    addr[0] = (byte) ((address >>> 24) & 0xFF);
    addr[1] = (byte) ((address >>> 16) & 0xFF);
    addr[2] = (byte) ((address >>> 8) & 0xFF);
    addr[3] = (byte) (address & 0xFF);
    return addr;
  }

  /**
   * Returns the IP address string in textual presentation form.
   *
   * @return the raw IP address in a string format.
   * @since JDK1.0.2
   */
  public String getHostAddress() {
    return numericToTextFormat(getAddress());
  }

  /**
   * Returns a hashcode for this IP address.
   *
   * @return a hash code value for this IP address.
   */
  public int hashCode() {
    return holder().getAddress();
  }

  /**
   * Compares this object against the specified object.
   * The result is {@code true} if and only if the argument is
   * not {@code null} and it represents the same IP address as
   * this object.
   * <p>
   * Two instances of {@code InetAddress} represent the same IP
   * address if the length of the byte arrays returned by
   * {@code getAddress} is the same for both, and each of the
   * array components is the same for the byte arrays.
   *
   * @param obj the object to compare against.
   * @return {@code true} if the objects are the same; {@code false} otherwise.
   * @see java.net.InetAddress#getAddress()
   */
  public boolean equals(Object obj) {
    return (obj != null) && (obj instanceof Inet4Address) &&
        (((InetAddress) obj).holder().getAddress() == holder().getAddress());
  }

  // Utilities
    /*
     * Converts IPv4 binary address into a string suitable for presentation.
     *
     * @param src a byte array representing an IPv4 numeric address
     * @return a String representing the IPv4 address in
     *         textual representation format
     * @since 1.4
     */

  static String numericToTextFormat(byte[] src) {
    return (src[0] & 0xff) + "." + (src[1] & 0xff) + "." + (src[2] & 0xff) + "." + (src[3] & 0xff);
  }

  /**
   * Perform class load-time initializations.
   */
  private static native void init();
}
